Abstract
Abstract
In this paper the behaviors of strength and deformation of short reinforced concrete column specimens wrapped with CFRP were studied through testing 48 cylindrical specimens under axial loading. The role of parameters of CFRP wrap layers and arrangement, concrete strength , main steel reinforcement , lateral reinforcement and specimen slenderness ratio was studied. Results indicated that due to wrapping with CFRP layers the state of confined concrete occurs and the properties of strength and deformation are modified considerably. The ultimate load percentage was found to vary from 123% to 280% of that of unconfined specimens. The ductility of reinforced concrete specimens was found to be increased considerably as a result of wrapping. The effect of wrapping was found to be important in the case of concrete of lower strength and poorly reinforced with both main bars and lateral reinforcements. In order to obtain higher load capacity of wrapped high strength concrete it should be reinforced highly with both types of reinforcements. In general the parameters influencing the behavior reinforced concrete confined with CFRP sheets are: number of layers, replacing layers with strips, concrete compressive strength, main bars, lateral reinforcement, and specimens slenderness ratio. An analytical model was proposed for calculating ultimate load capacity and load-strain relationship for reinforced NSC and HSC confined with CFRP sheets. The predictions were found to be accurate, and the ratio of test / calculated ultimate load was found to be 1.0043 for NSC and 1.0033 for HSC.
Keywords: Axial strain, Column, Confined concrete, High strength concrete, Lateral strain, Strengthening, Wrapping
